A projection device is a common electro-optical display device and has been extensively utilized for living entertainments, academic presentation, and business demonstration. According to different display principles, projection devices can be categorized into cathode-ray tube (CRT), liquid crystal display (LCD), digital light processing (DLP), and liquid crystal on silicon (LCoS) projectors.
Projectors, such as DLP projectors, may modulate the light beams from its light source with one or more light valves such as a digital micro-mirror device (DMD), and project images onto a projection screen via a projection optical system. The projectors may perform color separation for color display by using a wheel capable of wavelength conversion.
A typical wheel may comprise phosphor powder and a wheel plate. The area of light exposure of the phosphor powder coated on the wheel plate would increase with rotation of the wheel plate. Calibration of the dynamic balance of the wheel plate is required during production to maintain its rotational stability. Most calibration approaches adopt a carrying unit attached onto the wheel plate, followed by fixing an object for balance onto a specific position of the carrying unit to increase the weight at the specific position. However, attachment of the carrying unit onto the wheel plate tends to decrease the area of heat dissipation of the wheel plate.
Besides, when considering adding a light transmissive sheet with specific optical effects to the wheel plate, a holding component is required to fix the light transmissive sheet onto the wheel plate. However, the addition of the holding component would partially cover the wheel plate and thus decrease the area of heat dissipation of the entire wheel plate. Moreover, addition of the holding component would increase the processing and cost of the production of the wheel, thus raising concerns about the reduction of reliability of the wheel.
The information disclosed in this “BACKGROUND OF THE INVENTION” section is only for enhancement understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Furthermore, the information disclosed in this “BACKGROUND OF THE INVENTION” section does not mean that one or more problems to be solved by one or more embodiments of the invention were acknowledged by a person of ordinary skill in the art.